Give cornices a wide berth.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
An unsettled westerly flow is expected to bring around 5-10 cm snow on Wednesday, with moderate to strong winds and the freezing level around 1500 m. Snow showers linger on Thursday before a ridge brings clearing skies on Friday.
Avalanche Summary
No new avalanches were reported yesterday. Over the last week we have received many reports of cornice failure.
Snowpack Summary
Large cornices overhang some slopes. Deep and hard wind slabs can also be found in alpine areas. Below around 2300 m, a couple of crust layers are buried in the upper snowpack. No recent avalanche activity has been reported on these crusts. Snow surfaces have become moist up to around treeline with recent warm weather. Deeply buried weak layers near the ground may remain sensitive to triggering from thin snowpack areas.
Problems
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.